Performance of agency-managed and farmer-managed irrigation systems: A comparative case study at Chitwan, Nepal     

Kiran Prasad Bhatta  Akira Ishida  Kenji Taniguchi  Raksha Sharma 《Irrigation and Drainage Systems》2006,20(2-3):177-191

Management reforms are considered one of the best alternatives in increasing efficiency of the irrigation systems. Transfer of day-to-day operation and maintenance to farmers is not a new concept. However due to lags, even now it is a hot issue in developing countries and Nepal is not an exception. In this context of growing argument about the transfer of management of public irrigation systems to the Water Users' Group, this paper examines the comparative performance of farmer-managed and agency-managed irrigation systems. Khageri Irrigation System in the Chitwan district of Nepal was taken as the study site where complete management transfer has been done in 1996. The situations before and after complete transfer were compared. Intensive case studies of the selected farmers showed that equity in distribution of water and leakage had significantly improved after management transfer. Logit analysis revealed that age and education level of the household head, distance from main canal, leakage of the canal and equity in distribution are significantly related to the satisfaction level of the beneficiary farmers from FMIS compared to AMIS. However, landholding size of the respondent farmer has no significant effect. Similarly results from t-test revealed that rice productivity and overall profits from agriculture has also increased significantly due to irrigation management transfer.  相似文献   

Adsorption kinetics of 17α-ethinyl estradiol and bisphenol A on carbon nanomaterials. II. Concentration-dependence     

Bo Pan  Ke Sun  Baoshan Xing 《Journal of Soils and Sediments》2010,10(5):845-854

Purpose  

Carbon nanomaterials (CNMs) have attracted a great deal of research interest for their potential environmental applications because of their unique properties. Adsorption of organic chemicals on CNMs was reported to be important in controlling their environmental risks. However, the kinetics of the adsorption is hardly investigated in literature. The objective of this work was, therefore, to quantitatively describe the sorption kinetics of 17 α-ethinyl estradiol (EE2) and bisphenol A (BPA) on CNMs as compared to activated carbon (AC).  相似文献   

Biochemical properties,molecular characterizations,functions, and application perspectives of phytases     

Ruijuan Li  Jinfeng Zhao  Chuanfan Sun  Wenjing Lu  Chengjin Guo  Kai Xiao 《Frontiers of Agriculture in China》2010,4(2):195-209

As a kind of enzyme widely existing in eukaryotic species, especially in grains and oil seeds, phytases play an important role in the degradation of some phosphates containing organic molecules. So far, phytases derived from various species have been successfully used as animal feed additives. It has also been experimentally verified that phytases have a potential use in generating crop germplasm with high phosphorus use efficiency, based on their biochemical role in releasing Pi from the phytate and its derivatives. In this paper, the biochemical properties, molecular characterizations, functions and the potential application perspective of phytases are reviewed and commented on, aiming at the further exploration of the biochemical and molecular characterizations, and promotion of the application of phytases, a kind of important enzyme possessing potential use in animal feeding and creation of high P use crop cultivars, in the future.  相似文献   

Contributing traits for nitrogen use efficiency in selected wheat genotypes and corollary between screening methodologies     

Rumesh Ranjan  Ashish Kumar  Swarupa Nanda Mandal 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(7):588-595

ABSTRACT

Nitrogen uptake being part of nitrogen use efficiency (NUE) is largely decided by root traits. Root traits variability has hardly been explored by breeders mainly because of difficulties in scoring. The hydroponic system requiring lesser space for precise phenotyping of large numbers of genotypes independently of the growing season can be a suitable alternative. However, the effectiveness of hydroponic screening methods needs to be verified under the soil condition of the field or pot. In the present study, root traits and NUE were investigated in 19 genotypes under two conditions (hydroponic and pipe filled with soil). Both environments revealed large variability for root traits and NUE under high and low N conditions establishing the absence of any direct selection for these traits in the past. Under both sets of experimentation, NUpE was largely responsible for improved nitrogen efficiency mainly because of higher root biomass. The significant association between the two screening methods i.e. hydroponic and pot filled with soil under both low and high N condition support large scale screening for root traits under hydroponic condition.  相似文献   

Organization and promoter analysis of the zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>) chemokine gene (CXC-64) promoter     

Li-Chen Chen  Jen-Leih Wu  Chyuan-Yuan Shiau  Jyh-Yih Chen 《Fish physiology and biochemistry》2010,36(3):511-521

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Identification of molecular markers linked to the genes for purple grain color in wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis>)     

Xing-Pu Li  Su-Que Lan  Ye-Lun Zhang  Yu-Ping Liu 《Genetic Resources and Crop Evolution》2010,57(7):1007-1012

Pericarp color in wheat is an important trait related to nutrients and health benefits. Identification of molecular markers closely linked to the grain color genes will help utilize pericarp trait in wheat breeding. Genetic studies involving F₁, F₂, and F₃ populations from the cross Jizi 439 (purple grain)/Gao8901 (white grain) showed that the purple grain color was controlled by two genes. By using the bulked segregant analysis (BSA) approach, two DNA pools were established from the dark purple-grain and white-grain plants respectively. Among the 230 pairs of microsatellite primers used in this study, two markers showed polymorphism in DNA pools, parents, F₁ and F₂ populations. Linkage analysis indicated that the two markers Xgwm47 and Xgwm155 were linked with two purple pigment genes. One of the purple pigment genes is located on chromosome 2AS and is 34.7cM away from the marker Xgwm47, whereas another gene is mapped on 3AL with 14.7cM away from marker Xgwm155.  相似文献   

C. Clare Hinrichs and Thomas A. Lyson (eds.): Remaking the North American Food System: Strategies for Sustainability     

Molly D. Anderson 《Agriculture and Human Values》2009,26(3):251-252

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Support vector machine-based QSPR for the prediction of glass transition temperatures of polymers     

Xinliang Yu 《Fibers and Polymers》2010,11(5):757-766

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Food provisioning strategies,food insecurity,and stress in an economically vulnerable community: the Northern Cheyenne case     

Erin Feinauer Whiting  Carol Ward 《Agriculture and Human Values》2010,27(4):489-504

Living in poverty is associated with high levels of protracted stress associated with health problems. Economic and food insecurity are particularly poignant aspects of poverty and condition the work of securing basic daily needs of families. Recent studies suggest that levels of stress increase as family food needs rise. This paper presents new findings which clarify the relationship of food provisioning to stress levels, by examining actual food provisioning strategies and food insecurity among the Northern Cheyenne Indians of southeastern Montana. Results clearly show that stress varies by types of food acquisition strategies. Contrary to our expectations, more complex strategies, including relatively unpredictable and cumbersome food provisioning activities, are not linked to higher stress levels in our analysis. Controlling for food security levels, households using a combination of local programs and informal subsistence sources are the least stressed, despite the demands of managing a large number of food sources. Households primarily using Food Stamps are the most likely to experience high levels of stress. Interviews with Food Stamp recipients show that potential sources of stress include inadequate allocations of Food Stamps, difficulty achieving and maintaining eligibility, challenges to complying with paperwork and appointment requirements, as well as personal obstacles and community barriers to making food stamps last. Analyses indicate that contradictions between local cultural norms for food provisioning and the realities of food insecurity in this context promote strategies emphasizing greater independence from federal food programs.  相似文献   

Molecular divergence and application of the ITS-5.8S rDNA and RUBISCO spacer in <Emphasis Type="Italic">Porphyra haitanensis</Emphasis> Chang et Zheng (Bangiales,Rhodophyta)     

Changsheng Chen  Chaotian Xie  Dehua Ji  Yan Liang  Lingmin Zhao 《Aquaculture International》2010,18(6):1045-1060

To select a reliable and sensitive method for discriminating strains of Porphyra haitanensis, the nucleotide sequence of the internal transcribed spacer 1 to internal transcribed spacer 2 regions (ITS-5.8S) of nuclear ribosomal DNA and the intergenic spacer region of RUBISCO were compared in five wild and five cultivated Porphyra haitanensis strains. Based on molecular analyses, sequences of ITS-5.8S (about 1,210 bp) could be divided into three regions: ITS1, 5.8S, and ITS2. The ITS1 and ITS2 sequences of each strain differed, even between individuals collected from the same site. In contrast, 5.8S rDNA and RUBISCO spacer sequences were identical among the ten P. haitanensis strains, although differences were found among different Porphyra species. Phylogenetic analysis also supported these conclusions. These sequence features of highly conserved regions and diversified regions that occurred repeatedly in ITS-5.8S could be useful in discriminating germplasm of P. haitanensis strains or Porphyra species. In contrast, the RUBISCO spacer is only suitable for identifying Porphyra species. New coupled primers were designed to amplify only the 5.8S rDNA and ITS2 region of Porphyra. The sequences of these amplified fragments can be readily used to identify germplasm or to perform phylogenetic analysis of Porphyra spp.  相似文献